1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly, to a ball grid array (BGA) semiconductor package and a method of fabricating the same. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for increasing a mounting density in a stackable BGA semiconductor package.
2. Discussion of the Related Art
As a semiconductor device becomes increasingly smaller, thinner, and lighter, a high-density semiconductor package has been widely studied to mount more semiconductor chips in one package. A stacked TSOP (thin small outline package) has been used to mount a high capacity semiconductor chip since it has a thickness about one half of a related BGA semiconductor package.
The related BGA package has a wide lead pitch and a resistance to an external lead from an external impact. Also, a mass production is readily realized with this type of BGA package. However, a stackable package can not be fabricated using the structure of the related BGA package.
FIG. 1 is a cross-sectional view illustrating the structure of the related BGA semiconductor package. As shown therein, the BGA semiconductor package includes a substrate 1 having a plurality of through holes 3. Interconnection portions 5 are formed on upper and lower surfaces of the substrate in a predetermined pattern and filled into the through holes 3. A is semiconductor chip 7 is attached on a center portion of the upper surface of the substrate 1. A plurality of wires 9 connecting a plurality of pads (not shown) are formed on one side surface of the semiconductor chip 7. The interconnection portions 5 are also formed on the upper surface of the substrate 1. A solder resist 11 covers the upper and lower surfaces of the substrate 1 and the portions of the upper and lower surfaces of the interconnection portions 5. A molding body 13 is embedding the semiconductor chip 7 and the wires 9, and a plurality of solder balls 15 are respectively connected with the lower ends of the interconnection wires 5.
In the above related BGA package, it is impossible to fabricate a stackable package by stacking a plurality of BGA packages since the solder balls are formed on the lower surface of the substrate due to its design limitations. In addition, the above BGA semiconductor package has a lower mounting density compared to other stackable packages having the identical mounting area.